Drill string protector and system



W N. LAUGHLIN DRILL STRING PROTECTOR AND SYSTEM Aug. 23, 1966 4 Sheets-Sheet 1 Filed May 11, 1965 3, 1966 w. N. LAUGHLIN 3,268,275

DRILL STRING PROTECTOR AND SYSTEM Filed May 11, 1965 4 Sheets-Sheet 2 KKQQQW ATTO/P/VEVJ 3, 1966 w. N. LAUGHLIN DRILL STRING PROTECTOR AND SYSTEM 4 Sheets-$heet 15 Filed May 11, 1965 I NVENTOR.

Aug. 23, 1966 w. N. LAUGHLlN 3,268,275

DRILL STRING PROTECTOR AND SYSTEM Filed May 11, 1965 4 Sheets-Shee't i W////am /V. Zauy/z ///7 INVENTOR.

BY 1 (MM? MA 45 4 v United States Patent 3,268,275 DRILL STRING PROTECTOR AND SYSTEM William N. Laghlin, 102 Buckingham Drive, Lafayette, La. Filed May 11, 1965, Ser. No. 458,821 6 Claims. (Cl. 3084) This application is a continuation-impart of my copending application Serial No. 288,238, filed June 17, 1963, now abandoned.

This invention relates to drill string protectors and is particularly concerned with an improved protector device and system.

In the drilling of Well bores for the production of subterranean resources, such as oil and gas, the drill string may become damaged by repeatedly striking the Walls of the bore hole. And, when the bore hole is cased, this repeated impingement by the drill string may damage both the drill string and the casing.

To protect against such damage, thick walled, relatively hard, elastic bands usually called protectors, or pipe protectors, or casing protectors are placed around joints of the drill pipe at spaced intervals. Some applications employ a continuous band, which is stretched in diameter, by means of special tools, until it can be passed over the tool joint and onto the drill pipe. This type of protector is, however, relatively difficult to install and remove and requires the availability of proper tools. Further, after several stretchings this type of protector loses its elasticity and must be discarded. Other applications employ a split-type band which may be placed around the drill pipe while open and then latched or fastened, again, by means of appropriate tools. And both types suifer the disadvantage of requiring location along the drill pipe some distance from the tool joint there-by leaving the tool joint (which is the largest, and hence most vulnerable portion of the string) unprotected.

Another difiiculty with conventional protectors is their susceptibility to upward migration under the influence of the well-bore fluid pressure. As a result, it is not uncommon to find a single pipe joint carrying twenty or more protectors that have migrated up from down hole there by leaving portions of the string completely unprotected. Moreover, when the protectors migrate together they restrict fluid circulation causing abnormal down-hole pressures. When this occurs, of course, a disastrous blowout can and some times does occur.

An object of this invention is to provide a means and system for locating drill string protectors at the tool joint itself which, as above indicated is the focal point of damage.

Another object of the present invention is to provide a drill string protector and system adapted to permit installation and removal of the protector device without the necessity for stretching and/ or latching appliances.

A further object is to provide positive securement of the protector against longitudinal movement relative to the drill string.

Other objects and advantages of this invention are pointed up by the illustrations of certain embodiments shown in the appended drawings.

In general the present invention contemplates .a protector device comprising a resilient, reinforced, longitudinally compressible sleeve and a tool joint having a zone of reduced diameter over which the reinforced protector may be manually applied when the joint is uncoupled and within which the protector will be longitudinally compressed to achieve frictional engagement between protector and joint when the pin and box halves of the joint are snugly coupled.

More particular characterization of the present inven tion may be had by studying those certain embodiments thereof which are illustrated in the appended drawings and described in the following portion of this specification.

In the drawings:

FIGURE 1 is an elevation, partly in section, illustrating application within the system of one embodiment of the reinforced protector device.

FIGURE 2 is an enlarged partial section of the protector device of \FIGUR-E 1 and shows how longitudinal compression frictionally engages the protector device and the tool joint.

FIGURE 3 is an enlarged partial section of an alternate embodiment showing frictional engagement only at the band ends.

FIGURE 4 is a section elevation of another embodiment of the protector device showing employment of a continuous helix-defining reinforcing member.

FIGURE 5 is a sectional elevation of another embodiment of the protector device.

FIGURE 5 is an elevation view illustrating a tool joint wherein each half is provided with an annular shoulder.

FIGURE 7 is an enlarged partial section showing a box-half turned down to provide a zone of reduced diameter having an inwardly-cut shoulder member.

FIGURE 7A is an alternative form of the embodiment shown in FIGURE 7 and illustrates employment of an outwardly-cut shoulder member.

FIGURE 8 is an isometric showing a pin-half provided with a zone of reduced diameter comprising three flats.

FIGURE 9 is an elevation, partly in section illustrating a conventional joint, swelled and split.

\FIGURE 10 is a section elevation showing employment of a single hard steel reinforcing collar.

FIGURE 11 is an alternate embodiment illustrating employment of a hard body outfitted with resilient end members.

FIGURE 12 is a sectional elevation of still another embodiment of the protector device according to this invention.

Reference numerals have been used as follows:

(1) Resilient body (2) Rings (3) Pin-half (4) Box-half (5) Tool joint (6) Body end portions (7) Zone of reduced diameter (8) Protector device (9) Helix-defining member 10) Shoulder (11) Shoulder 12) Extruded portions (13 Rings (14) Flats (15) Collar (16) Swell (17) Split (18) Hard body (19) Resilient end members (20) Adapter (21) Resilient insert (22) Hard body Referring now to FIGURES 1 and 2:

The conventional drill string is, of course, comprised of a plurality of sections of any convenient outside diameter suitable for running in a borehole. FIGURE 1 illustrates such a section of a drill string which contains an area of enlarged diameter or tool joint comprised of a threadably coupled pin-half 3 and box-half 4. However, unlike conventional tool joints, a portion of boxhalf 4 and a relatively small portion of pin-half 3 have been turned down, as by means of a grinding lathe, to provide an annular recess or zone 7, intermediate the ends of the joint, which has a smaller overall outside diameter than the overall outside diameter of the joint itself. Thus, when box-half 4 is uncoupled from pinhalf 3 a protector device 8 embodying this invention may be manually slid over and mateably received by zone 7 of box-half 4.

Protector 8 is conveniently provided by a resilient body 1, as for example of rubber, reinforced throughout substantially its entire length by a plurality of spaced, hard steel rings 2 embedded in body 1 adjacent its inner face. The overall outside diameter of body 1 is, as illustrated, larger than the overall outside diameter of joint 5. Moreover, body 1 is slightly longer than reduced diameter zone 7. Thus, when protector '8 is placed over zone 7 of box-half 4 and box-half 4 and pin-half 3 are snugly coupled, body 1 of protector 8 is placed under longitudinal compression. When this longitudinal compression occurs the portions 12 of body 1 disposed between rings 2 are extruded against zone 7 to frictionally engage joint 5 and protector 8 against relative movement.

As illustrated in the embodiment of FIGURE 3, body 1 may be provided with enlarged end portions 6 which will extrude against zone 7, as illustrated, in the event it is desired to economize on reinforcement by spacing rings 2 so far apart that portions 12 are extruded outwardly. However, this arrangement is not preferred and sacrifices protector-to-joint engagement effectiveness.

Various other embodiments may also be employed, including, but not limited to:

A single, helix-defining reinforcing member such as member 9 of FIGURE 4 which may, if desired, be so provided with an adapter 20 at its terminal ends so that about 360 of bearing surface is provided, as shown in dotted line in FIGURE 4. A frusto-conical collar 15 (see FIG. 10 re collar) or a plurality of frusto-conical rings 13 such as those shown in FIGURE 5 may also be employed. The use of frusto-conical reinforcement however, contemplates employment of a tapered zone 7 shouldered at only one end, i.e., shoulder 11 as illustrated in FIGURE 5.

Further, the pipe joint may be provided with a reduced diameter zone 7 by extraneously forming annular shoulder members 10 and 11, as by metallizing techniques, on the pin and box halves 3 and 4 as shown in FIGURE 6. And, if desired, the shoulder members may be angulated inwardly or outwardly as illustrated in FIG- URES 7 and 7A respectively. And, it is equally feasible to provide joint 5 with reduced diameter zone 7 by cutting two or more flats 14 into either pin-half 3 or box-half 4, as generally illustrated in FIGURE 8. Of course, if zone 7 is comprised of flats then the inner wall of body 1 of protector 8 will desirably be of mating configuration.

Further, employment of reinforcement such as rings 2 or 13, or body 18, or collar 15 of high strength steel or the like, as variously shown in the several figures of the drawings will provide the joint 5 with additional hoop strength thereby offering significant protection against 4 joint damage by swelling and splitting such as shown in FIGURE 9 where a joint 5 has swelled at 16 and split at 17.

Another embodiment which is often found to be desirable is illustrated in FIGURE 12. The protector 26 of this embodiment comprises steel rings 22 fitting into the annular shoulder members at each end of the protector, and one or more sections 21 of an elastomer such as rubber, which elastomeric sections are narrow in width at the outside edge of the protector, but taper out to become much wider at the point at which they engage the joint 5. This feature of the protector, i.e., the greater cross-section of the elastomeric insert in at least one direction at the inner face of the protector, provides a protector which is strong, durable and relatively inexpensive. It will be understood that the elastomeric insert of this embodiment can be of any suitable shape just so long as it has relatively little surface area at the outer edge of the protector-and a relatively large area at the inner face.

From the foregoing, it may be seen that the present invention will admit of various embodiments. And, while certain specific embodiments have been illustrated and described herein to facilitate understanding of the invention, the actual scope of the invention itself must be determined by reference to the appended claims.

What is claimed is:

1. A drill string protector system comprising:

a tubular drill string comprised of a plurality of engageable sections, each said section having an outside diameter suitable for insertion of the string into a borehole;

said drill string having areas of enlarged diameter at the points where said sections are joined to each other;

an annular recess in the outer surface of at least one of said areas of enlarged diameter;

:a resilient sleeve defining an inner surface and an outer surface inserted into said recess and engaging said area of erdarged diameter over the entire length of the inner surface of said sleeve,

wherein a plurality of spaced metal rings are imbedded in said sleeve adjacent said inner surface so as to be in contact with said area of enlarged diameter of said drill string.

2. The invention according to claim 1, wherein said annular recess is formed over the junction of two sections of drill string.

3. The invention according to claim 1, wherein said sleeve is slightly greater in length than said annular recess.

4. A drill string protector system comprising:

a tool joint having pin and box halves, threadedly connected and cooperating to define a zone intermediate the ends of said joint having an overall outside diameter smaller than the overall outside diameter of said joint;

a resilient generally tubular sleeve mateably surrounding said joint in said zone, said sleeve containing at least one reinforcing member adjacent the inner surface of said generally tubular sleeve for engagement with the surface of said tool joint in said reduced diameter zone, whereby upon longitudinally compressing said sleeve, portions of said sleeve are extruded around said reinforcing member into frictional engagement with the surface of said tool joint, to thereby prohibit movement of said sleeve.

5. The system in accordance with claim 4, wherein said sleeve is slightly greater in length than said zone, to thus achieve said longitudinal compression.

6. The system of claim 4, wherein said zone comprises a portion of said joint lying between first and second spaced annular shoulders, said first shoulder being formed around said box-ha1f and said second shoulder being formed around said pin-half.

References Cited by the Examiner UNITED STATES PATENTS Mack 308-4 Smith 308-4 Smith 308-4 Hopkins 285-16 X Morris 308-237 X Patterson 308-4 McLane 175-325 X Smith 308-4 Dufify 285-333 X Wright 175-325 X Ricefield 64-11 Crickmer 277-235 Johnston 277-235 X Lee 64-3 X Boice 308-4 Lane 308-4 Hall 308-4 DAVID J. WILLIAMOWSKY, Primary Examiner. DON A. WAITE, Examiner.

L. L, JOHNSON, Assistant Examiner. 

1. A DRILL STRING PROTECTOR SYSTEM COMPRISING: A TUBULAR DRILL STRING COMPRISED OF A PLURALITY OF ENGAGEABLE SECTIONS, EACH SAID SECTION HAVING AN OUTSIDE DIAMETER SUITABLE FOR INSERTION OF THE STRING INTO A BOREHOLE; SAID DRILL STRING HAVING AREAS OF ENLARGED DIAMETER AT THE POINTS WHERE SAID SECTIONS ARE JOINED TO EACH OTHER; AN ANNULAR RECESS IN THE OUTER SURFACE OF AT LEAST ONE OF SAID AREAS OF ENLARGED DIAMETER; A RESILIENT SLEEVE DEFINING AN INNER SURFACE AND AN OUTER SURFACE INSERTED INTO SAID RECESS AND ENGAGING SAID AREA OF ENLARGED DIAMETER OVER THE ENTIRE LENGTH OF THE INNER SURFACE OF SAID SLEEVE, WHEREIN A PLURALITY OF SPACED METAL RINGS ARE IMBEDDED IN SAID SLEEVE ADJACENT SAID INNER SURFACE SO AS TO BE IN CONTACT WITH SAID AREA OF ENLARGED DIAMETER OF SAID DRILL STRING. 